#!/usr/bin/env python3
"""Turn a line number in dist/index.html into the source file and line it came from.

  python3 tools/where.py 4211          ->  src/sim/pipes.js:57
  python3 tools/where.py < error.txt   ->  the text with every index.html:LINE rewritten

Browser errors point into the built page. build.py writes dist/bundle-lines.json, which says where
each source file starts in it. Rebuild first if the sources changed since the error.
"""
import json, pathlib, re, sys

ROOT = pathlib.Path(__file__).resolve().parent.parent


def load():
    return json.loads((ROOT / 'dist' / 'bundle-lines.json').read_text())['files']


def where(line, files=None):
    files = files or load()
    best = None
    for start, f in files:
        if start <= line: best = (start, f)
        else: break
    return f'src/{best[1]}:{line - best[0] + 1}' if best else f'index.html:{line} (before the script)'


def translate(text, files=None):
    files = files or load()
    return re.sub(r'(?:file://)?[^\s()]*index\.html:(\d+)(:\d+)?', lambda m: where(int(m.group(1)), files) + (m.group(2) or ''), text)


if __name__ == '__main__':
    if len(sys.argv) > 1:
        for a in sys.argv[1:]: print(where(int(a)))
    else:
        print(translate(sys.stdin.read()), end='')